The subject invention relates to memory device structure and organization and more particularly to a variable dimension and variable orientation method of organizing a bit-map. The bit-map organization allows characters to be placed in the bit-map in any of four orientations, and the bit-map accommodates any height-to-width ratio of an output device so long as the total number of bits required by the output device is less than the number of bits in the bit-map.
Such a memory device has application in systems for printing the output of such devices as word processors, and particularly in interfacing between a character generator ROM and a laser printer. In such apparatus, it is desirable to have the capability to print characters in various orientations on the page, for example, a page number in one orientation and graphical data at right angles thereto. Such printing can be accomplished by using additional ROM storage to store each character in several orientations. It has appeared to the inventor that a different strategy may be used which provides flexibility and greatly reduced ROM storage requirements. The subject invention provides a memory organization and a technique for generating addresses to the memory to permit input and output of characters in various orientations. The objects of the invention are several:
1. Make a bit-map memory for an output device that has variable height and width parameters.
2. Allow characters to be entered in the array in any orientation: normal, upside down, rotated 90.degree. either left or right.
3. Easily change the number of bits in the bit-map by adding additional devices.